1. Field of the Invention
The present invention relates to an aerodynamically contoured filter which removes foreign particles from a fluid, and more particularly, to a filter using surface filtration to remove contaminants from air, as air laden with particulates and aerosols is circulated through the filter.
2. Background Art
Pollutants, pollen, dust particles, and other foreign particles are often introduced in the air supply of closed rooms, such as the passenger compartments of vehicles. The problem with air pollutants in vehicles is particularly acute in high traffic densities, or in severe climates with high contents of dust, smog, fog, industrial effluents, or the like.
Many attempts have been made to remove pollutants, pollen, dust paticles, and other foreign particles from the air by using filtration systems. Conventionally, filtration devices which pass the air through filter media such as mats or screens are inserted in the intake channel of the vehicle cabins to filter out these contaminants. To effectively filter out small particles, the mesh of the screen must be small. The small mesh often becomes blocked after a short period of time, and it is necessary to frequently clean or change the filter element. The small mesh also produces a pressure drop, which is the major limiting factor involved in applying a filter in the intake duct of a ventilation system for a vehicle.
PCT Application PCT/De87/00489 describes a foraminous, multi-layered filter, impregnated with glycerine. The filter includes numerous apertures, such that the apertures of one layer are offset with respect to the apertures of the adjacent layers. However, such a filter is inadequate for vehicles equipped with air conditioning, since there exists too great a pressure drop across the filter.
The problems enumerated above have prevented the application of an ultra-fine particle filter in the ventilation system of a vehicle. All vehicles are critically dependent upon an adequate supply of fresh air to enable proper defrosting and defogging. It is also imperative that people with chronic allergic and asthmatic conditions have continual supply of fresh air in all driving environments. accordingly, the inability to supply the vehicle cabin with an adequate supply of fresh air can be a distinct health and safety hazard.